I have already changed the APN settings exactly the same way I did for my wife's phone. Data would not work, received error saying I was not subscribed to a cellular data plan or something like that... Called and the tech support person I was connected with said that my AT&T iPhone was not unlocked because I did not get the cellular data network screen and that she could not help me until I got it unlocked, despite the big congratulations you iPhone is unlocked screen I got in iTunes and telling her about the SIM swap method I had used one my phone and my wife's currently functioning iPhone. I see on this board many people having the same problem - how did you fix it?

Hi andydye. My name is Straight Talk Jennifer. Sorry that you’re having a problem. I’m going to try to help you now. We need to take this issue offline, so I can address it further. I will contact you directly with a private message. Thank you.